n = int(input())
c = input()

red = c.count('R')
print(c[red:].count('R')) n = int(input()) n int(input()) int input() input c = input() c input() input red = c.count('R') red c.count('R') c.count c count 'R' print(c[red:].count('R')) print c[red:].count('R') [red:].count [red:] c red: red count 'R' n = int(input()) int(input()) n red = c.count('R') c.count('R') red c = input() input() c
n = int(input())
c = input()

red = c.count('R')
print(c[red:].count('R'))